The invention relates to a composition for polishing the surface of a polishing object containing a metal, for example, in a semiconductor integrated circuit (hereinafter referred to as the “LSI”).
New fine processing techniques have been developed as the LSI in highly integrated and increased in speed. The chemical mechanical polishing (hereinafter, referred to as the “CMP”) method is also one of them and is a technique that is applied in the LSI manufacturing process, especially for the flattening of the interlayer insulating membrane in the multilayer wiring forming process, the formation of contact plug and the formation of embedded wiring. This technique is disclosed, for example, in Patent Literature 1.
In the formation of contact plug, tungsten is used as the embedded material and the material for the mutual diffusion barrier thereof. In the formation of contact plug, a manufacturing method to remove the excess part other than the contact plug by CMP is used. In addition, in the formation of embedded wiring, the utilization of copper or a copper alloy as a metal wiring serving as the wiring material has recently been attempted in order to enhance the performance of LSI. For copper or a copper alloy, the so-called damascene method in which a thin membrane of copper or a copper alloy is deposited on the insulation membrane having a groove formed in advance and embedded and the thin membrane other than the groove portion is removed by CMP to form the embedded wiring is mainly employed since it is difficult to perform the fine processing by the dry etching method which has been frequently used in the formation of aluminum alloy wiring of the related art. It is general that the polishing composition for metal used in CMP contains a polishing accelerator such as an acid and an oxidant and further contains abrasive grains if necessary. In addition, it has also been proposed to use a polishing composition further containing a metal corrosion inhibitor in order to improve the flatness of the polishing object after polishing. For example, it is disclosed in Patent Literature 2 that a polishing composition containing an amino acetic acid and/or an amidosulfonic acid, an oxidant, benzotriazole and water is utilized. However, there is room for improvement upon the fact that the step such as dishing (a phenomenon in which the metal wiring layer is excessively polished) gets worse although a high polishing rate is achieved in the case of conducting the CMP method using the composition disclosed in Patent Literature 1 or Patent Literature 2. Furthermore, a polishing composition which contains abrasive grains, a specific additive and water and has a surface tension regulated at a certain value or less is disclosed in Patent Literature 3 in order to solve these problems.